Apparatus and method for processing signal, recording medium, and program

Abstract

A signal processing apparatus includes a decoding unit, an analyzing unit, a synthesizing unit, and a selecting unit. The decoding unit decodes an input encoded audio signal and outputs a playback audio signal. When loss of the encoded audio signal occurs, the analyzing unit analyzes the playback audio signal output before the loss occurs and generates a linear predictive residual signal. The synthesizing unit synthesizes a synthesized audio signal on the basis of the linear predictive residual signal. The selecting unit selects one of the synthesized audio signal and the playback audio signal and outputs the selected audio signal as a continuous output audio signal.

Description

CROSS REFERENCES TO RELATED APPLICATIONS [0001] The present invention contains subject matter related to Japanese Patent Application JP 2006-236222 filed in the Japanese Patent Office on Aug. 31, 2006, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an apparatus and a method for processing signals, a recording medium, and a program and, in particular, to an apparatus and a method for processing signals, a recording medium, and a program capable of outputting a natural sounding voice even when a packet to be received is lost. [0004] 2. Description of the Related Art [0005] Recently, IP (Internet protocol) telephones have attracted attention. IP telephones employ VoIP (voice over Internet protocol) technology. In this technology, an IP network, such as the Internet, is employed as part of or the entirety of a telephone network. Voice data is compressed using a variet...

AI Technical Summary

Benefits of technology

[0010] Accordingly, the present invention provides an apparatus and a method for processing signal, a recording medium, and a program capable of outputting natural sound even when a packet to be received is lost.

[0013] The linear predictive residual signal generating means can further generate a second feature parameter, and the synthesizing means can generate the synthesized audio signal on the basis of the first feature parameter and the second feature parameter.

[0019] When the pitch gain is smaller than a reference value, the periodic residual signal generating means can generate the periodic residual signal by reading out the linear predictive residual signal at random positions thereof instead of repeating the linear predictive residual signal in accordance with the pitch period.

[0027] As noted above, according to the embodiments of the present invention, even when a packet is lost, the number of discontinuities of a playback audio signal can be reduced. In particular, according to the embodiments of the present invention, an audio signal that produces a more natural sounding voice can be output.

Problems solved by technology

However, in the technique described in Japanese Unexamined Patent Application Publication No. 2003-218932, unnatural sound like a buzzer sound is output, and it is difficult to output sound that is natural for human ears.

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